Enhanced multiclass support vector data description model for fault diagnosis of gears

This work reports a study aimed at identifying the operating state of gear through an enhanced multiclass support vector data description (eMSVDD) model where the multiple hyperspheres corresponding to different operating states of gears are established. The model addresses the following issues: (1) the overlap of multiple hyperspheres deteriorates the diagnostic performance for boundary samples and severely weakens the generalization ability of the model; (2) the original support vector data description can only be applied to handle binary classification tasks; and (3) the performance of the SVDD depends heavily on the penalty factor C and kernel parameter delta. In the proposed model, we first implement the multi-label classification task by building multiple hyperspheres. Then, a novel fitness function for adaptive simplified chaotic particle swarm optimization is proposed to determine the model parameters, which considers the empirical risk minimization and model generalization capability. Finally, experimental results demonstrate that the eMSVDD outperforms deep neural networks and support vector machine by 3.4% and 0.5%, respectively, and this performance improvement respectively reaches 17.8% and 2.1% in the case of a very small sample size. The proposed approach provides a means for gear fault diagnosis with small samples.